High frequency semiconductor elements cascaded on a line require an elongated package.
Heat dissipation performance of a high frequency semiconductor element such as HEMT (high electron mobility transistor) is improved when bonded onto a metal plate. This requires housing the high frequency semiconductor element in a frame body of e.g. ceramic in order to hermetically seal the high frequency semiconductor element.
In the process for manufacturing a package and/or the process for bonding a high frequency semiconductor element, the package warps due to the difference in linear expansion coefficient between the metal plate and the ceramic frame body. The amount of warpage of the package can be reduced by shaping the package like a square. However, the package is elongated with the increase in the number of cascaded elements.